A proximity sensor is used to detect the existence of an object and a distance to the object. The proximity sensor includes a light emitting element and a light receiving element. The object is irradiated with light from the light emitting element and reflected light from the object is received in the light receiving element. In general, a light emitting diode (LED) is used as the light emitting element of the proximity sensor. Many proximity sensors employ a package structure for reducing crosstalk caused by diffused light of the light emitting diode.
In a photo-reflector device, a light emitting element and a light receiving element individually sealed by a light transmissive resin are further sealed by a light shielding resin to be optically isolated from each other, thereby reducing crosstalk.
In a proximity sensor, optical isolation between a light emitter and a photodetector is made by an opaque metal housing. Diffused light is condensed by a lens arrangement formed above the light emitter, thereby reducing crosstalk.
In another proximity sensor, a VCSEL (Vertical Cavity Surface Emitting Laser) is used as a light emitting element. In this proximity sensor, the VCSEL and a light receiving element are disposed on a substrate.
FIGS. 17A and 17B are a sectional view and a plane view, respectively, showing one example of a conventional optical measuring device including a light emitting element and a light receiving element. In the optical measuring device 100 shown in FIGS. 17A and 17B, the light emitting element 101 and the light receiving element 102 individually sealed by a light transmissive resin are further sealed by a light shielding resin 103 to be optically isolated from each other. In addition, two lenses 104 are optically isolated from each other by a light shielding wall 106. Therefore, light emitted from the light emitting element 101 is reflected by the lenses 104 or an inner wall of a case 105, thereby preventing the light from being directly incident onto the light receiving element 102. In addition, an inter-lens distance control part 107 is disposed inside the case 105. Further, a temperature sensor 108 is disposed inside the light receiving element 102.
However, the above-described photo-reflector device is complicated in structure and is increased in size since the light shielding resin is formed between the light emitting element and the light receiving element so as to create an optical isolation between the light emitting element and the light receiving element.
The above-described proximity sensor is complicated in structure and is increased in size since the opaque metal housing is formed between the light emitter and the photodetector so as to make the optical isolation between the light emitter and the photodetector and the lens arrangement is formed.
The above-described proximity sensor does not have a specified structure to protect the VCSEL and the light receiving element by means of a light transmissive resin.
The above-described optical measuring device 100 shown in FIGS. 17A and 17B is complicated in structure and is increased in size since the light shielding resin 103 is formed between the light emitting element 101 and the light receiving element 102 so as to make the optical isolation between the light emitting element 101 and the light receiving element 102, two lenses 104 are disposed, and the light shielding wall 106 is formed between the two lenses 104.